The technology described herein relates to a method for high integrity and high availability at the source processing that places minimal design constraints on the software applications (Hosted Applications) that are hosted on a computer processing module (Module) such that they can still run on typical normal integrity computer processing modules.
Computer processing modules (Modules) can provide high integrity and high availability at the source to ensure that faults are detected and isolated with precision and that false alarms are minimized. High integrity Modules are even more important for aircraft, whereby a fault that is not promptly and accurately detected and isolated may result in operational difficulties. The proper detection and isolation of faults in a module that provides high integrity at the source is sometimes referred to as the ability to establish fault containment zones (FCZ) within the module or system, such that a fault is not able to propagate outside of the FCZ in which it occurred. Also, it is important that high integrity Modules should also have a very low probability of false alarms, since each false alarm may result in a temporary loss of function or wasted computer resources to correct a purported problem that does not in fact exist.
Conventional designs for high integrity at the source Modules require expensive custom circuitry in order to implement instruction level lock-step processing between two or more microprocessors on the Module. The conventional instruction level lock-step processing approaches provide high integrity to all of the hosted applications but may be difficult (or impossible) to implement with state of the art microprocessors that implement embedded memory controllers and input/output support requiring multiple Phase Lock Loops (PLLs) with different clock recovery circuits.
There is a need for a high integrity at the source design for a Module which places minimal design constraints on the Hosted Applications (i.e. the same Hosted Application can also be run on a typical normal integrity Module) and which is capable of utilizing high speed microprocessors (e.g., integrated processors).